Electrochemical investigations of antioxidant interactions with radical anion and dianion of 1,3-dinitrobenzene

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• 作者：Nasima Arshad ; Naveed Kausar Janjua ; Safeer Ahmed ; Athar Yaseen Khan ; Leif H. Skibsted
• 关键词：Antioxidants ; Cyclic voltammetry ; 1 ; 3-Dinitrobenzene ; Homogeneous bi-molecular rate constant ; Scavenging trends
• 刊名：Electrochimica Acta
• 出版年：2009
• 出版时间：1 November 2009
• 年：2009
• 卷：54
• 期：26
• 页码：6184-6189
• 全文大小：704 K

文摘

Interactions of five antioxidants (AO), quercetin (Q), morin (M), rutin (R), ascorbic acid (AA) and β-carotene (β-C) with anion radical and dianion of 1,3-dinitrobenzene (1,3-DNB) in two aprotic solvents – dimethyl formamide (DMF) and dimethyl sulfoxide (DMSO) – have been studied by cyclic voltammetry using glassy carbon electrode. Electrochemical parameters – peak potential (E_p), half-wave potential (E_1/2), and peak current (i_p) – for the reduction of 1,3-DNB before and after the addition of various concentrations of antioxidants, were evaluated. A gradual decrease in the oxidation peak current and finally irreversibility in 1,3-DNB radical anion and dianion systems upon the addition of antioxidant, reveals their interactions. The homogeneous bi-molecular rate constant (k₂) was determined from electrochemical data. In comparison to all other antioxidants used, enhanced homogeneous second order rate constant for the interaction of morin with 1,3-DNB anion radical and dianion, was observed. This aspect is attributable to protonation initiated by hydrogen bonding and greater acidic nature of morin.